1. Field of the Invention
The present invention relates to an electrophoretic instrument, and particularly to an electrophoretic instrument using a capillary filled with a gel of a medium for separating samples as an electrophoretic lane.
2. Prior Art
The PCT Japanese patent publication No. 11-511555 discloses a replacing means in which the old gel inside a capillary of a gel replacing system is replaced by the new gel delivered by a pump.
In the prior art described above, the manual operation to open the valve inserted between the charging syringe and the injection syringe when the injection syringe is charged with the gel. Therefore, the measurement must be temporarily suspended, and as the result, processing ability of the analysis is lowered.
Further, in the PCT Japanese patent publication No. 11-511555, there is no description on automatic gel charging during measurement.
An object of the present invention is to provide an electrophoretic method and an electrophoretic instrument which can perform gel charging during continuous analysis, and accordingly can improve the processing ability of analysis.
In order to attain the above object, according to one aspect of the present invention, there is provided an electrophoretic instrument which comprises a gel injection mechanism for injecting a gel of a medium for separating samples into one or more capillaries; and a check-valve for preventing back-flow of the gel to a gel charging syringe arranged between a gel injection syringe and the gel charging syringe.
In the present invention, a polymer gel is used as the electrophoretic separation medium, and a labeled sample to be analyzed is moved in the polymer gel of electrophoretic separation medium during performing electrophoresis.
According to another aspect of the present invention, there is provided an electrophoretic instrument comprising a capillary; a gel injection mechanism for injecting a gel of a medium for separating a sample into the capillary; and a detection unit for optically detecting elctrophoretically separated compositions of the sample introduced into the capillary, wherein the gel injection mechanism comprises an injection syringe for injecting the gel into the capillary; a charging syringe for charging the injection syringe with the gel; a block having a flow passage connecting the both syringes, the capillary and a buffer reservoir; and a check valve for preventing the gel from flowing back to the charging syringe. It is preferable that the check valve described above is constructed so as to prevent the gel from flowing back to the charging syringe when the gel is injected from the injection syringe into the capillary. It is preferable that the flow passage of the block is composed of a first flow passage communicating between the charging syringe and the injection syringe; and a second flow passage for communicating between the injection syringe and the capillary. It is preferable that a branching passage to the buffer reservoir, into which an electrode used at performing electrophoresis is inserted, is provided at a middle position of the second flow passage. The examples of concrete structures are as follows.
(1) An electrophoresis method comprising the steps of supplying a gel for electrophoresis to a bore of an injection syringe; driving a plunger of the injection syringe by a motor; injecting the gel into a bore of a capillary through a block having a flow passage communicating to the capillary; and supplying an analyzed sample to the capillary to separate the sample by electrophoresis, the method further comprising the steps of detecting an amount of the gel remaining in the injection syringe; driving a plunger of a charging syringe to charge the flow passage in the block with the gel when the value of amount is smaller than a predetermined amount of the gel, the charging syringe being connected to the flow passage in the block through a check valve; then supplying the gel to the capillary by the plunger of the injection syringe.
(2) The electrophoresis method, wherein the capillary is a capillary array having a plurality of capillaries, and a sample is electrophoretically moved from sample supply ends serving as a cathode of the capillaries toward a buffer reservoir serving as an anode.
(3) The electrophoresis method further comprising the steps of obtaining amounts of the gel in the injection syringe and the charging syringe using encoders; injecting an amount of the gel necessary for once of the electrophoresis into the capillaries; then checking an amount of the gel remaining in the injection syringe; and supplying an amount of the gel necessary for the second and thereafter electrophoreses from the charging syringe into the injection syringe as required.
(4) The electrophoresis method further comprising the steps of exciting the sample separated by the electrophoresis using an electromagnetic wave; and detecting fluorescence generated by the excitation.
(5) An electrophoretic instrument comprising a capillary; a gel injection mechanism for injecting a gel of a sample separating medium into the capillary; a detecting unit for detecting a sample introduced into the capillary and electrophoretically separated; an injection syringe with a plunger for injecting the gel into the capillary; a charging syringe with a plunger for performing charging with the gel; a block in which a flow passage connecting among the syringes, the capillary and a buffer reservoir is formed; a check valve for preventing the gel from flowing back to the charging syringe, the check valve being arranged between the charging syringe and the flow passage; and an encoder for obtaining an amount of the gel in the injection syringe.
(6) The electrophoretic instrument further comprises a light source for exciting the electrophoretically separated sample; and a detector for detecting fluorescence generated by the excitation.
(7) The electrophoretic instrument, wherein the flow passage of the block is composed of a first flow passage communicating between the charging syringe and the injection syringe, and a second flow passage communicating between the injection syringe and the capillary.
(8) The electrophoretic instrument, wherein a branching passage to the buffer reservoir is provided at a middle position of the second flow passage, an electrode used at performing electrophoresis being inserted into the buffer reservoir.
(9) The electrophoretic instrument further comprises motors for driving the injection syringe and the charging syringe.
(10) The electrophoretic instrument further comprises a control unit for controlling a driving amount and sequence of the motor using a signal of the encoder.
(11) The electrophoretic instrument, wherein it is detected from a signal of the encoder that the plunger of the syringe is in contact with a drive unit.